Multicenter study investigating long-term survival after synovial lavage of contaminated and septic synovial structures in horses presented to 10 UK referral hospitals.

OBJECTIVE: To report the long-term survival of adult horses that were subjected to synovial lavage for treatment of contaminated and septic synovial structures. STUDY DESIGN: Multicenter, prospective observational trial. ANIMALS: Horses (n = 240) presented for synovial sepsis at 10 UK referral centers. METHODS: Data for horses presented for treatment of synovial sepsis were collected over a 15 month recruitment period. Owners were contacted a minimum of 365 days after surgery using a structured client interview to assess long term survival. Descriptive statistics, and univariable and Cox proportional hazards models for postoperative survival time were developed. RESULTS: Survival to discharge was 228/240 (95%) and overall long-term survival was 89.4% (185/207). Unknown cause of injury (p = .017), increasing duration of surgery (p = .003), increasing weight (p = .008), forelimb injuries (p = .027), and type of synovial structure (p = .008) were found to be associated with death using Cox proportional hazards models. CONCLUSION: This study provides information on risk factors associated with survival and death after treatment for synovial sepsis at referral hospitals in the UK. Survival to discharge and long-term survival was excellent. Heavier horses, injuries affecting the forelimbs, tendon sheaths and bursae were associated with poorer long term outcomes. Longer duration of surgery was also found to be associated with a worse prognosis. CLINICAL SIGNIFICANCE: These findings help to provide prognostic information for owners and veterinarians treating horses with synovial sepsis.

Efficacy and dermal tolerance of a novel alcohol-based skin antiseptic in horses.

OBJECTIVE: To determine the efficacy and dermal tolerance of a novel alcohol-based skin antiseptic (ABSA) in horses. STUDY DESIGN: Experimental study. ANIMAL POPULATION: Systemically healthy horses (n = 25) with no history or clinical signs of skin disease. METHODS: Four clipped sites on the abdomen were randomly assigned to a skin preparation protocol: saline (negative control; NC), chlorhexidine gluconate followed by isopropyl alcohol (positive control; PC), saline followed by the ABSA (ABSA A), or a commercially available horse shampoo followed by the ABSA (ABSA B). Microbiological swabs were obtained from each site and cultured on MacConkey and mannitol salt agar plates. Colony-forming units were counted 18-24 hours later. All sites were scored for signs of skin reaction before, immediately after, 1 hour after, and 24 hours after skin preparation. RESULTS: The PC, ABSA A, and ABSA B methods reduced skin microbial burden compared with the NC method (P < .001), but no difference was detected between antiseptic products. Preparation time did not differ between ABSA A and ABSA B methods (P = 0.108); both were faster than the PC method (P < 0.001 for both). Skin reactions were most abundant 24 hours after skin preparation (30.5%), but there was no significant association with antiseptic used, and no horses required veterinary treatment. CONCLUSION: The ABSA preparations tested in this study were as effective and well tolerated as a chlorhexidine gluconate-based method, but required less time in healthy horses. CLINICAL SIGNIFICANCE: The ABSA tested here provides an efficacious, fast-acting, and well-tolerated alternative to achieve skin antisepsis in healthy horses. These results justify further investigation in clinical cases.

Development of a Novel Medial Synoviocentesis Approach to the Bicipital Bursa in an Equine Cadaver Model.

OBJECTIVE: To describe the volume and dimensions of the bicipital bursa and its position in relation to bony and soft tissue structures, in order to develop a novel medial synoviocentesis approach to the bicipital bursa. STUDY DESIGN: Cadaveric study. ANIMALS: Adult equine cadaver limbs (n=19). METHODS: Bicipital bursa dimensions, volume, and relationship to bony structures were obtained from positive contrast computed tomography images after distension of the bursa (n=7). Following an intra-bursal injection of polyurethane resin, the bicipital bursa (n=4) was dissected and its relationship to soft tissue structures described. After computed tomography and dissection, a novel medial bicipital bursocentesis approach was investigated on intact cadavers (n=8). RESULTS: Median (range) of measurements were: length 9.02 cm (8.48-9.45 cm); width 7.06 cm (6.71-8.01 cm); and volume 51 mL (45-58 mL). The medial aspect of the bicipital bursa was located at the junction of the subclavius and biceps muscles, which corresponds with the externally visible lateral pectoral sulcus. Needle insertion 5-10 mm craniolateral to the center of the lateral pectoral sulcus midway between the palpable distal aspect of the deltoid tuberosity and the cranial part of the greater tubercle was found to be a reliable landmark for the novel medial bursocentesis approach. This approach was successful in all cadavers. CONCLUSION: The novel approach to the bicipital bursa provided access to the medial aspect of the bursa and is an alternative to the lateral approaches. Further validation in live horses is warranted to establish the safety and efficacy of this technique.

A scoping review of the current evidence on treatment and outcomes following synovial sepsis.

BACKGROUND: Synovial sepsis is a frequent cause of morbidity and mortality in horses. Despite advances in diagnostics and treatments, persistent infection or chronic lameness can occur. OBJECTIVES: To perform a scoping review to identify and evaluate the current evidence on the factors implicated in the success of treatment for synovial sepsis. STUDY DESIGN: Joanna Briggs Institute scoping review. METHODS: A protocol was registered, and a systematic literature search was performed on CAB abstracts, Medline, Scopus and Embase. Inclusion and exclusion criteria were developed and studies systematically reviewed against this. Studies relating to factors affecting treatment success following synovial sepsis were retained and data was extracted on study method, population characteristics and factors significantly associated with treatment outcome. RESULTS: In total, 2338 studies were identified, and 61 were included to full paper analysis. Eight papers reported significant factors, identifying 15 risk factors associated with two measurements of outcome, either survival and/or return to athletic function. The 15 factors were identified and categorised into pre-, intra- and post-operative factors. Risk factors that were identified included the number or type of synovial structures involved, the presence of pannus, tendon and bone pathology, and the use of systemic antimicrobials. There were many discrepancies in inclusion criteria of cases of synovial sepsis as well as measurement and description of outcome variables. MAIN LIMITATIONS: Non-English language studies or conference proceedings were not included. Only small numbers of papers had similar findings. CONCLUSIONS: Standardisation of inclusion criteria is essential to enable comparisons and analysis between studies on synovial sepsis. Future studies should use methodologies to reduce bias including multicentre and multinational studies, prospective study design and robust statistical modelling.

Effects of glucocorticoids and interleukin-1 beta on expression and activity of aggrecanases in equine chondrocytes.

OBJECTIVE: To determine effects of interleukin (IL)-1 beta and glucocorticoids on total glycosaminoglycan (GAG) loss and aggrecanase-mediated matrix degradation in equine cartilage. SAMPLE POPULATION: Cartilage from 24 equine cadavers free of sepsis and musculoskeletal disease. PROCEDURES: Effects of IL-1 beta, IL-1 beta with glucocorticoids (dexamethasone and triamcinolone, 10(-6) and 10(-7)M), and glucocorticoids alone on degradation of equine articular and nasal cartilage explants were assessed by measuring GAG release in media and GAG content in cartilage. Aggrecanase-mediated cleavage within the interglobular domain at Glu373-Ala374 was evaluated via western blot analysis and ELISAs. Steady-state mRNA concentrations of matrix metalloproteinase (MMP)-3, MMP-13, a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS)4, and ADAMTS5 were assessed by use of real-time reverse transcriptase PCR assay (cartilage explants) and northern blot analysis (cell culture). RESULTS: IL-1 beta increased GAG release and aggrecanase activity (11-fold). The MMP-3, MMP-13, and ADAMTS4 mRNA were upregulated with IL-1 beta, whereas ADAMTS5 mRNA was increased (13-fold), but significantly less than ADAMTS4 mRNA (27-fold), suggesting a role for both ADAMTS4 and ADAMTS5 in degradation of cytokine-stimulated cartilage. Despite downregulation of MMP-3 and MMP-13 mRNA, glucocorticoids did not alter GAG degradation. A further increase in aggrecanase activity was detected with ELISAs and western blot analysis, whereas ADAMTS4 mRNA was downregulated and ADAMTS5 mRNA was maintained or upregulated. CONCLUSIONS AND CLINICAL RELEVANCE: MMP-3, MMP-13, and ADAMTS4 were regulated differently than ADAMTS5. Glucocorticoids increased aggrecanase activity despite down-regulation of ADAMTS4 mRNA, suggesting a major role of ADAMTS5. Effects of glucocorticoids on aggrecanase activity have important implications in terms of treatment.

Acquired jejunal pseudodiverticula in a yearling Arabian filly.

OBJECTIVE: To report a case of multiple acquired jejunal pseudodiverticula managed successfully by resection and jejunojejunostomy. STUDY DESIGN: Clinical report. ANIMALS: Arabian filly. METHODS: The filly was referred for signs of acute colic of several hours duration and had a 2-week history of inappetence and weight loss. Three meters of thickened, edematous, and dilated jejunum removed during exploratory celiotomy had an intussusception and numerous diverticula; jejunojejunostomy performed. The pathoanatomic diagnosis was proliferative enteropathy with pseudodiverticula formation and jejunal muscular hypertrophy and diverticulosis. The diverticula appeared to be acquired; however, the exact cause was not determined. RESULTS: There were no postoperative gastrointestinal complications and 1 year later, the filly was doing well. CONCLUSION: Multiple acquired jejunal pseudodiverticula not associated with classic muscular hypertrophy can occur in young horses. Long-term prognosis seemingly can be excellent after resection and jejunojejunostomy. CLINICAL RELEVANCE: Compared with other reports of small intestinal diverticula in horses, this case is unique because it was not congenital or associated with classic muscular hypertrophy.

Extraluminal, C shaped polyethylene prostheses in two ponies with tracheal collapse.

OBJECTIVE: To describe the surgical technique, complications, and outcome after use of extraluminal prostheses in 2 ponies with severe tracheal collapse. STUDY DESIGN: Clinical report. ANIMALS: Ponies (n=2) with severe tracheal collapse. METHODS: A ventral median approach was used to expose the trachea from the larynx to the manubrium. Extraluminal, high-density polyethylene, C-shaped prostheses were sutured to the dorsal tracheal membrane and tracheal rings to provide external tracheal support. RESULTS: The surgical approach provided good tracheal access and placement of the rings was uncomplicated. Initial estimates of the tracheal diameter from preoperative radiographs resulted in prostheses that were too small at surgery requiring a 2nd surgical procedure in 1 pony. Postoperative complications were coughing, right laryngeal hemiplegia, seroma formation, and antimicrobial induced colitis. Both ponies had marked resolution of clinical abnormalities after surgery. Recurrent esophageal obstruction resulted in euthanasia of 1 pony 3.5 years after surgery. The other pony was doing well 1 year after surgery. CONCLUSIONS: Extraluminal support of the trachea resulted in rapid resolution of clinical signs in 2 ponies with tracheal collapse. CLINICAL RELEVANCE: Extraluminal tracheal prostheses can resolve clinical abnormalities in ponies with severe tracheal collapse.

Surgical repair of mid-body proximal sesamoid bone fractures in 25 horses.

OBJECTIVE: To describe the characteristics of unilateral mid-body proximal sesamoid bone (PSB) fractures, to determine factors associated with the outcome of horses after surgical repair, and to describe a technique for arthroscopically assisted screw fixation in lag fashion. STUDY DESIGN: Retrospective case series. ANIMALS: Horses (n=25) with unilateral mid-body PSB fracture. METHODS: Medical records (1996-2006), radiographs, and arthroscopic videos of horses with surgically repaired unilateral mid-body PSB fractures were reviewed. Retrieved data included signalment, affected limb and PSB, fracture characteristics, and surgical technique. Outcome was established by radiographic assessment of healing and race records; categorical data were analyzed using Fisher's Exact test. RESULTS: Medial forelimb PSBs were most commonly affected (80%). Surgical technique and degree of reduction were significantly associated with outcome; 44% of horses with screw repair and none of the horses with wire fixation raced (P=.047). Factors that may have influenced this outcome were differences in fracture reduction (improved reduction in 22% wire repairs and 88% screw repairs, P=.002) and use of external coaptation (22% wire repair and 88% lag screw repair, P=.002). None of the horses with unimproved reduction raced after surgery. CONCLUSIONS: Only 28% of horses with mid-body PSB fractures raced after surgery. Compared with wire fixation, screw fixation in lag fashion resulted in good reduction and is seemingly a superior repair technique. CLINICAL RELEVANCE: For mid-body PSB fractures, arthroscopically assisted screw fixation in lag fashion and external coaptation for anesthesia recovery and initial support provides the best likelihood of return to athletic use.

Arthroscopically assisted arthrodesis of the distal interphalangeal joint with transarticular screws inserted through a dorsal hoof wall approach in a horse.

CASE DESCRIPTION: A 16-year-old Thoroughbred gelding was examined because of chronic right forelimb lameness. CLINICAL FINDINGS: On radiographs of the right front foot, the distal interphalangeal (DIP) joint space was narrow, and osteophytes and periarticular bony proliferation indicative of severe osteoarthritis were seen. Arthrodesis of the right DIP joint was recommended to improve the horse's comfort on the limb. TREATMENT AND OUTCOME: The horse was anesthetized, and palmar and dorsal arthroscopic approaches were used to remove as much of the articular cartilage as was accessible. Holes were then drilled through the dorsal aspect of the hoof wall, and 3 transarticular, 5.5-mm cortical screws were placed in lag fashion through these holes across the distal phalanx and into the middle phalanx. Defects in the hoof wall were filled with gentamicin-impregnated polymethyl methacrylate plugs and sealed with cyanoacrylate. Eight months after surgery, fusion of the DIP joint was evident radiographically and the horse was sound at a walk. CLINICAL RELEVANCE: Transarticular placement of cortical screws through a dorsal hoof wall approach combined with arthroscopically guided cartilage removal can result in fusion of the DIP joint in horses.

Coll2-1, Coll2-1NO2 and myeloperoxidase concentrations in the synovial fluid of equine tarsocrural joints affected with osteochondrosis.

The measurement of biomarkers that reflect cartilage breakdown is a powerful tool for investigating joint damage caused by disease or injury. Particularly in cases of osteochondrosis, synovial concentrations of these biomarkers may reveal the presence of osteoarthritic changes. Coll2-1, Coll2-1 NO2 and myeloperoxidase have recently been introduced in equine osteoarticular research but comparison between the concentrations of these markers in OCD affected and healthy joints has not been made. Therefore, this study aimed at reporting the synovial concentrations of these biomarkers in joints affected with osteochondral fragments in the tarsocrural joint compared to unaffected joints. Myeloperoxidase and Coll2-1NO2 revealed to have similar levels between affected joints and controls. However, in contrast to previous studies using C2C the present study demonstrated that synovial levels of Coll2-1 were significantly elevated in tarsocrural joints affected with osteochondrosis. Thus, Coll2-1 may be an earlier marker of cartilage degeneration than other cartilage degradation markers that have been previously used in equine medicine.

European outbreak of atypical myopathy in the autumn 2009.

BACKGROUND: Atypical myopathy is an acute, severe rhabdomyolysis occurring in grazing horses. In the beginning of October 2009, a new outbreak occurred in several European countries. Geographic, demographic and clinical data of the reported cases in the month October 2009 are described. KEY FINDINGS: The survival rate in this outbreak was 25%. The most frequently observed clinical signs were congested mucous membranes, dyspnea, tachycardia, depression, weakness, stiffness, recumbency, trembling, sweating, and myoglobinuria. Nonsurvivors were significantly more likely to be recumbent than survivors. Prognostic factors, symptomatic treatment, and preventive measures are discussed. SIGNIFICANCE: Differences were encountered during the described outbreak of atypical myopathy in October 2009 compared with previous outbreaks reported. Equine practitioners should be aware that previous epidemiological studies have shown that after a high prevalence in the autumn, new cases are likely to occur in the following spring.